libnvdimm: remove redundant __func__ in dev_dbg

Dynamic debug can be instructed to add the function name to the debug
output using the +f switch, so there is no need for the libnvdimm
modules to do it again. If a user decides to add the +f switch for
libnvdimm's dynamic debug this results in double prints of the function
name.

Reported-by: Johannes Thumshirn <jthumshirn@suse.de>
Reported-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
diff --git a/drivers/nvdimm/claim.c b/drivers/nvdimm/claim.c
index b2fc29b..3085227 100644
--- a/drivers/nvdimm/claim.c
+++ b/drivers/nvdimm/claim.c
@@ -148,7 +148,7 @@ ssize_t nd_namespace_store(struct device *dev,
 	char *name;
 
 	if (dev->driver) {
-		dev_dbg(dev, "%s: -EBUSY\n", __func__);
+		dev_dbg(dev, "namespace already active\n");
 		return -EBUSY;
 	}